Joker ups rent outrageously (7)
I believe the answer is:
punster
'joker' is the definition.
(I've seen this before)
'ups rent outrageously' is the wordplay.
'outrageously' indicates an anagram.
'ups'+'rent'='upsrent'
'upsrent' with letters rearranged gives 'PUNSTER'.
(Other definitions for punster that I've seen before include "Comedian" , "One makes jokes" , "Verbal joker" , "user of wordplay" , "One playing on words" .)